The invention relates to a measuring device having at least one semiconductor arrangement including a semiconductor chip connected to a carrier having at least one through-hole. The semiconductor chip has at least one sensor with an active sensor surface facing the through-hole and has electrical terminal points connected using flip-chip connections to terminal contacts located on the carrier and facing the terminal points. The carrier has electrical strip conductors which connect the terminal contacts to contact elements on the carrier. At least one strip conductor carrier is provided having opposing contacts connected to the contact elements and to strip conductors, at least a portion of the strip conductor carrier being arranged on the rear of the carrier and having contact elements with opposing contacts facing the contact elements of the carrier. The opposing contacts of the strip conductor carrier are connected using flip-chip connections to the contact elements of the carrier, which are allocated to each of them. The semiconductor chip and the carrier enclose a measurement chamber, and a seal is arranged between the carrier and the semiconductor chip.
A measuring device of this type is known from John H. Lau, Flip Chip Technologies, pages 260 and 261, McGraw-Hill (1995). There, the through-hole is covered on one of its axial ends by the semiconductor chip and on its other axial end by the strip conductor carrier. In the coverage area the strip conductor carrier has openings connected to supply and discharge channels for a fluid to be investigated which is conducted through the measuring chamber. On the rear side of the carrier, facing away from the semiconductor chip, the strip conductor carrier is connected by an adhesive layer to the edge area of the carrier that surrounds the through-hole. Between the semiconductor chip and the carrier a gap is formed, in which polymer bumps are arranged, which connect the terminal points of the semiconductor chip to the terminal contacts of the carrier respectively allocated to them. Between the active sensor surface and the polymer bumps a sealing ring is arranged as a seal, which seals off the fluid located in the test space from the polymer bumps and the rear side of the semiconductor chip facing away from the active sensor surface. The sealing ring has a sealing surface on each of its flat sides, one of which rests on the semiconductor chip and the other rests on the carrier.
Measuring devices of this type are used, for example, for chemical and/or biological tests on a medium located in the measuring chamber. It is necessary during the measurement, for certain tests therein, to bring two different substances into the through-hole simultaneously, but separated from each other, and to supply them to the sensor, for example if these substances react chemically with each other and this chemical reaction should be monitored using the sensor. In the previously known device, however, different substances in the fluid stream can only be supplied together, i.e., the substances must already have been brought into contact with each other outside the measurement chamber.
A measuring device of the type set forth at the outset is also already known from German published patent application DE 198 10 060 A1. There, the semiconductor chip is constructed as an active structural component, which releases a substance upon heating. In addition, an additional substance can be brought into the measuring chamber through the opening of the through-hole. The measuring device, however, has the disadvantage that, in addition to the chip area on the semiconductor chip which is necessary for the sensor, additional space must be provided in order to accommodate the substance to be released, and possibly the heating unit for heating up this substance. Since the costs for manufacturing a semiconductor chip increase superproportionally with the increase in size of the chip area, the measuring device is comparably more expensive. Also, with the selection of the substance to be released certain limitations must be taken into account, since not all substances allow for a release upon heating. Finally, the measurement result can also be affected by the introduction of heat.
Thus, an object of the invention is to create a measuring device of the type described at the beginning, which allows a compact construction and has accesses to the measuring chamber that are independent from each other. This object is achieved in that the seal for bringing a substance into the measuring chamber is constructed to be porous or semi-porous at least in certain areas. Through the seal, for example, an active substance can be brought into the test space formed by the through-hole of the carrier, for example to examine the effect of the active substance on the biological cells located there using the sensor of the semiconductor chip. The porous or semi-porous material of the seal may comprise, for example, aluminum oxide ceramic. The material preferably has pores or holes which permit transmission of substances or particles having sizes in the micrometer range. On the rear side of the seal, facing away from the through-hole, a reservoir, for example, can be arranged for the active substance or equivalent substance to be brought into the through-hole, and/or the seal is connected on the rear side to a supply channel for the substance. Optionally, the porous or semi-porous seal can also function as a filter for a medium to be brought into the through-hole.
The object mentioned above can also be achieved in that the seal for bringing a substance into the measuring chamber is constructed as a selectively permeable membrane. It is thereby possible to allow only certain chemical substances, which can diffuse through the membrane, to pass through the gap, and to prevent other substances from passing through the gap. The membrane thereby allows a sealing off of the through-hole located on the front side of the semiconductor chip, from the rear side of the semiconductor chip. Through the membrane, for example, certain active substances can be supplied to biological components located in the through-hole and arranged in a nutrient medium or an osmotic protective medium, in order to examine the reaction of the biological components using the semiconductor sensor. Gas-permeable membranes can, for example, be made of polyethylene permeable to hydrogen, lanthanum fluoride permeable to fluorine, or zirconium oxide permeable to oxygen. Other permeable materials for the membrane may include, for example, polyvinylchloride, polytetrafluoroethylene, or silicone rubber. The membrane arranged in the gap can have a directionally-dependent permeability.
The seal can be constructed as a form seal, which has one or more windows that leave open certain areas of the semiconductor chip. Also, the seal can project inwardly beyond the wall of the carrier that surrounds the surface plane of the through-hole, and in certain areas it can cover the cross-section of the through-hole. The area of the seal that projects inwardly beyond the edge of the carrier through-hole can then function as a support for a connection piece located in or insertable into the through-hole. The connection piece can have inlet and/or outlet openings for the medium to be tested and, optionally, can be part of a pump housing.
One embodiment of the invention provides that the seal is formed by a castable substance (potting compound) poured into the gap located between the semiconductor chip and the carrier. This allows a mechanically stable bond between the semiconductor chip and the carrier. Thus, for example, under excess pressure of a medium located in the through-hole, the pressure forces acting on the semiconductor chip can be transmitted to the carrier over a large area via the castable substance arranged on the peripheral edge of the semiconductor chip. In particular, the mechanical load on the flip-chip connections is also reduced thereby.
It is advantageous if the seal is optically transparent and/or is penetrated by at least one fiber optic light guide. It is thereby possible to illuminate the test space formed by the through-hole by going through seal, so that a medium located there can be observed optically. By the seal and/or the light guide, however, light signals can also be conducted out of the test space to the outside, for example with fluorescence of a specimen located in the through-hole.
Another embodiment of the invention provides that the semiconductor chip has an optical, in particular an image-transmitting sensor, and that at least one optical lens and/or at least one optical filter is arranged in the through-hole. The filter and/or the lens can be manufactured during the production of the measuring device by dripping an optically transparent material on the semiconductor chip or on a layer on top of it. The optically transparent material can then optionally be dried or cured by a chemical reaction. The semiconductor chip and/or the carrier can have an evaluation device, a storage unit for storing the image data and/or an interface module for transmitting the image data to a display and/or storage device located outside of the measuring device. On the whole, an economically producible, compactly constructed camera results therefrom. It is even possible therein that the carrier be constructed as a chip card.
An especially advantageous embodiment of the invention provides that the carrier has a plurality of through-holes, each having a semiconductor chip arranged there. The individual semiconductor chips can then, for example, have chemical sensors, so that in a laboratory a plurality of specimens can be tested at the same time. It is even possible therein that different semiconductor chips be arranged on the individual through-holes and that these, in particular, have different sensors. In this way, one or more different specimens can be tested at the same time for different chemical properties.
It is advantageous if on the side of the carrier facing away from the semiconductor chip, a support is arranged for supporting a form tool for forming a container on the edge area of the carrier that surrounds the through-hole, and if on the area of the carrier which surrounds the support, a plastic that forms the wall of the container is sprayed on. The form tool can then be set down on the carrier during the manufacture of the container, so that it is spaced from the semiconductor chip located behind it. Damage to the sensitive sensor surface by the form tool is thereby avoided. In addition, a sealed connection between the form tool and the carrier is achieved on the support, so that when spraying the plastic around in the form tool, the plastic cannot come into contact with the active sensor surface. The container forms, together with the through-hole of the carrier, a receptacle which optionally can have a defined volume, into which can be brought a specimen to be investigated with the sensor.
An especially advantageous embodiment provides that the measuring device be constructed as a microtiter measuring device having a plurality of semiconductor arrangements. In this embodiment, the carriers of the individual semiconductor arrangements are expediently each connected on their front side facing away from the semiconductor chip to an upper part of a microtiter plate, especially using an adhesive layer. The carriers of the individual semiconductor arrangements herein can also optionally be connected to each other as a single piece. As the microtiter plate upper part, a commercially available standard microtiter plate can optionally be provided. In order to fill the individual specimen containers of the microtiter measuring device, sampling devices already present in laboratories can then be used.
It should also be mentioned that in addition to the sensor of the semiconductor chip, optionally at least one sensor can be provided on the carrier as well, e.g., an ion-selective field effect transistor and/or an electrode. The carrier can also, however, have a treatment device for bio-components or similar specimens to be brought into the through-hole, which can include, for example, a heating unit and/or a cooling device. Furthermore, the carrier can have a transmitter and/or receiver for data transfer to an external control and/or evaluation (analysis) device.
The carrier can have contact elements, which are connected to the terminal contacts of the carrier using the strip conductors located on the carrier, wherein the carrier is at least partially made of a flexible or plastically deformable material for changing the position of the contact elements relative to the terminal contacts. The contact elements can then be connected to connections of an evaluation unit and/or a power supply unit adapted thereto, wherein the position of the contact elements can be adapted to the respective local conditions by deforming the carrier at the mounting site of the semiconductor arrangement. Thus, it is possible, for example, to pivot the terminal contacts relative to the plane of the chip and relative to the semiconductor chip by bending the carrier, so that the terminal contacts can be arranged, according to each situation on the mounting site, either on the front side of the semiconductor chip, laterally of the semiconductor chip and/or on its rear side.